No worries, i understand you were busy ;)
Actually i installed both plugins, ceceppa and add for customizer, setup 2 or 4 languages (same issue on another site), first site Italian and English, 2nd site Italian, english, french and german.
When i go to customize theme, and try do anything, like insert custom text/html, or any other plugin, wheter i do it on my local mamp or online the auto update stops and gives me that error.
So working with menus is ok because i translate them elsewhere but adding content from "customise" is almost impossible.
When i talk about customize, i'm talking about: Theme -> customize or Aspect -> Customize (where you setup site title and motto, add sidebars widgets etc.)
This was an issue on child themes with Hemigway and Twenty Fourteen Theme.
The child theme plugin i'm using is Child theme configurator (http://www.lilaeamedia.com/plugins/child-theme-configurator/). Mybe the issue is from this one?
hanks for any given help.